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Old 10-18-2004, 10:42 AM   #44
20th Level Warrior

Join Date: December 28, 2003
Location: Kentucky
Age: 32
Posts: 2,820
Originally posted by aleph_null1:
Originally posted by Ilander:
Anyway, so I can't figure out the integral of x sin^2 (x) dx... ...I've spent two hours thinking about it, and I'm no closer, as integration by substitution seems to get me nowhere...
I'm probably too late to be useful, but the answer is:

(x^2 / 4) - (1/8 * cos(2x)) - (1/4 * x * sin(2x))

You've to use the identity integral( sin(x)^2 ) == x/2 - 1/4 * sin(2x)

(whew... haven't integrated anything in a while )
[/QUOTE]Absolutely NOT too late to be useful!...I just could have sworn that we'd never seen that first part before, and whenever I don't think that I'm supposed to know how to do something yet, then I think that I'm going about the problem incorrectly...

Well, thanks, Aleph_null1, I sincerely appreciate it...Calculus II is pwning me so far, but hopefully, with enough studying, I can fix that!

Is that what you really want to say?
Ilander is offline